너무 보고 싶어서 잠이 안 와

The line, explained

It is two in the morning and the phone screen is the only light in the room. 너무 보고 싶어서 잠이 안 와, 'I miss you so much I can't sleep'. This line joins a cause to its result with one of the most common connectors in Korean, -아/어서. Where English says 'so much that' or 'because', Korean simply hooks the first verb onto the second, and the reason flows naturally into what happens next.

너무 means 'so' or 'too'. Strictly it meant 'too much', but today it is the everyday 'so, really': 너무 좋아, it's so good. 보고 싶어서 is built on 보고 싶다, 'to want to see', which is how Korean says 'to miss someone'. The stem 싶 has the vowel ㅣ, not ㅏ or ㅗ, so it takes -어서: 싶어서. Linked in speech, it becomes si-peo-seo.

-아/어서 follows the same vowel rule as the casual ending. Stems with ㅏ or ㅗ take -아서: 좋아서, 와서. Others take -어서: 먹어서, 싶어서. 하다 becomes 해서: 피곤해서, because I'm tired. Two things to remember. First, the tense lives only at the end: never say 싶었어서, even about the past. Second, the second half cannot be an order. For 'it's raining, so take an umbrella', Korean uses -(으)니까 instead.

잠이 안 와 literally means 'sleep doesn't come'. 잠 is sleep, the noun, and 이 marks it as the subject, linking the sound into ja-mi. 안 is 'not', placed before the verb, and 와 is the casual form of 오다, to come. Korean pictures sleep as a visitor who either arrives or stays away, so 'I can't sleep' becomes 'sleep isn't coming'. It is a small, poetic idiom you will hear constantly.

Sing it with a sigh: neo-mu bo-go si-peo-seo, then ja-mi an wa, trailing off. Now swap the reason and keep the sleepless night: 너무 설레서 잠이 안 와, I'm too excited to sleep; 너무 행복해서 잠이 안 와, I'm too happy to sleep. You can apologise with the same pattern too: 늦어서 미안해, sorry I'm late, literally 'I'm late, so I'm sorry'. Cause, then effect, every time.